I want to replace some incandescent bulbs with LEDs in a couple of diesel locomotives. I have some Miniatronics 5mm YeloGlo White LEDs, and the instructions call for 470 ohm resistors. But, that resistor value leaves the LED way too bright.
So, I tried a 1K ohm resistor, but the result was a still way too bright LED. Then, I tried a 5K ohm resistor. That reduced the brightness somewhat but still too bright.
I wound up with three 5K ohm resistors in series. I finally got a satisfactory brightness level, but that seems ridiculous - - a total of 15K ohms.
Besides, is there any risk of damage with that high a value?
Any thoughts or suggestions?
Rich
Alton Junction
Hmm, None of the ones I used were excessively bright at 1K - but the aren't direct view, they are always through light pipes.
I'm surprised they still too bright with 15K - that's 0.8mA! High efficiency for sure!
You can't hurt anything by running even LESS current through it.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
No. I’m curious, what current did you end up with? 800ųa? I have some of those super brights. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
RR_Mel No. I’m curious, what current did you end up with? 800ųa? I have some of those super brights. Mel
No. I’m curious, what current did you end up with? 800ųa? I have some of those super brights. Mel
rrinker Hmm, None of the ones I used were excessively bright at 1K - but the aren't direct view, they are always through light pipes.
I bought a 0-2 amp meter off eBay that has 5 digits for checking my LED lighting. Silly thing works so good I ordered a second. As I remember they were about $4.The meter is a panel mount and didn’t come mounted, I bought a box also off eBay to hold the meters. A real handy goodie is a small DC to DC converter for working with LEDs, variable regulated 0-12 volts at 2 amps. I mounted it in a like box, super handy for setting up LEDs.I use 4 volts for my passenger lighting and I set the converter to 4 volts so I don’t have to screw around setting the voltage on my bench power supply, any power from 5 volts up gives me the 4 volts out.
Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
Rich,
I ended up using 10K resistors with the 0603 SMD LEDs in my brass locomotive headlights and I think they look more prototypical:
Maybe smaller LEDs give the illusion that they are brighter? However, even with a 3mm LED and 1K resistor, the headlights can be pretty blinding.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
They (they newer SMD LEDs) are way more efficient than older LEDs - that translate into more light for less current. So having to use much more than the 'typical' 1K (which runs a typical white LED at or below half the maximum rating - which is a really good safety margin, at least to keep the LED from frying) is not too surprising. Having to go up to 15K on a more traditional leaded LED - I wonder if they are the same as the YeloGlo LEDs I bought years ago. Could be they are using a new supplier and they are deliverying high efficiency LEDs, which are available in leaded versions - typical red LEDs on 5 volts with a 470 ohm resistor were about right, but the high efficieny ones are absolutely blindlign and light up plenty bright on 5 volts with 1K or more.
There is something to say about the size, since if the light output is equal but one source is a 5mm globe and the other is maybe 1mm in the center of the SMD version, it will appear much brighter to the eye. Much of that though could jsut be losses in the material the LED is made out of - even clear, not diffused, 5mm and 3mm LEDs have a good deal of clear epoxy between the actual emitting point and where you view it. Crank down the current enough and you might be able to hold the 5mm LED up and see the tiny point where the light comes from with it powered.
EEVBlog on YouTube once got hold of a hight sensitive photodetector (like single digit numbers of photos would trigger it) and did a test with some LEDs. Even regulr ones, with insanely low currents - even in the dark your eye, and even better his camera, couldn't detect a glow - but this sensor did.
Here's what I found:
The headlight LED was burnt out in a recent purchase of an Atlas Silver series Dash 8-40CW.
I had some smd LEDs and so put one in. Way too bright compared to the backup light. In Lokprogrammer, I tried reducing the brightness but even at the lowest level it was barely acceptable, and the dimmer wouldn't work any more (not surprising). Atlas have 1K resistors in their LED +ve leads so I tried upping it to 2.2K which is the LokSound default. A lot better.
The thing about LEDs is that they maintain an even brightness way down until they start to turn off. It's a matter of limiting the current until you find that sweet spot where it's dimmer but still controllable.
tstage Rich, I ended up using 10K resistors with the 0603 SMD LEDs in my brass locomotive headlights and I think they look more prototypical
I ended up using 10K resistors with the 0603 SMD LEDs in my brass locomotive headlights and I think they look more prototypical
rrinker They (they newer SMD LEDs) are way more efficient than older LEDs - that translate into more light for less current. So having to use much more than the 'typical' 1K (which runs a typical white LED at or below half the maximum rating - which is a really good safety margin, at least to keep the LED from frying) is not too surprising. Having to go up to 15K on a more traditional leaded LED - I wonder if they are the same as the YeloGlo LEDs I bought years ago. Could be they are using a new supplier and they are deliverying high efficiency LEDs, which are available in leaded versions - typical red LEDs on 5 volts with a 470 ohm resistor were about right, but the high efficieny ones are absolutely blindlign and light up plenty bright on 5 volts with 1K or more.
Oldngrey The thing about LEDs is that they maintain an even brightness way down until they start to turn off. It's a matter of limiting the current until you find that sweet spot where it's dimmer but still controllable.
In this most recent instance, I tried a 1K resistor - - - way too bright. So, then I switched to a 5K resistor which didn't seem to reduce the brightness one bit. I added a second 5K resistor in series - - - still seemed to be the same level of brightness. Once I added the third 5K resistor, the brightness dimmed to a satisfactory level.
I use 3mm wide angle Super Bright LEDs for the lighting in my passenger cars and prefer realistic looking low level lighting. I went with 9.1KΩ resistors at 4 volts for the lighting on my current Athearn Mel kitbash lounge car. I used 9 of the 3mm wide angle Super Bright LEDs with 9.1KΩ resistors spaced at ⅞” in the ceiling to illuminate the lounge area and one with a 4.7KΩ resistor over the bar for a total of 4.8ma at 4 volts.The Super Bright LEDs are very efficient compared to the older LEDs. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
RR_Mel I use 3mm wide angle Super Bright LEDs for the lighting in my passenger cars and prefer realistic looking low level lighting. I went with 9.1KΩ resistors at 4 volts for the lighting on my current Athearn Mel kitbash lounge car. I used 9 of the 3mm wide angle Super Bright LEDs with 9.1KΩ resistors spaced at ⅞” in the ceiling to illuminate the lounge area and one with a 4.7KΩ resistor over the bar for a total of 4.8ma at 4 volts.The Super Bright LEDs are very efficient compared to the older LEDs.
I use 3mm wide angle Super Bright LEDs for the lighting in my passenger cars and prefer realistic looking low level lighting. I went with 9.1KΩ resistors at 4 volts for the lighting on my current Athearn Mel kitbash lounge car. I used 9 of the 3mm wide angle Super Bright LEDs with 9.1KΩ resistors spaced at ⅞” in the ceiling to illuminate the lounge area and one with a 4.7KΩ resistor over the bar for a total of 4.8ma at 4 volts.The Super Bright LEDs are very efficient compared to the older LEDs.
I found some Golden White LEDs this morning from another manufacturer that I had stored in a box. With a 1K resistor on the Golden White LED, the brightness level is much more subdued.
I have a bunch of loco that the headlights are the Miniatronics YeloGlow, with a 1K resistor, and they aren't excessively bright. Some are 5mm, some are 3mm. My P2K Geeps, my Trainline FA, a couple of my Stewart switchers - they came with an LED that was redily visible throught he headlight lens that was orange when off, so they got swapped. I did change the resistor on that - but they came with 470 ohm and I desoldered those and put in 1K.
FWIW, when I did the interior lighting for my McKeen Motor Car I used 30K resistors, one for each of the 16 or so interior lamps. The LEDs glowed just like a very early incandescent bulb, which was the effect I wanted. In fact, I could have gone with a higher value resitor because when all the lights in the room are out, the interior lamps are still a bit too bright.
As others have said, you can't hurt the LEDs by trying higher value resistors.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
rrinker I have a bunch of loco that the headlights are the Miniatronics YeloGlow, with a 1K resistor, and they aren't excessively bright. Some are 5mm, some are 3mm.
I have a bunch of loco that the headlights are the Miniatronics YeloGlow, with a 1K resistor, and they aren't excessively bright. Some are 5mm, some are 3mm.
rrinker My P2K Geeps, my Trainline FA, a couple of my Stewart switchers - they came with an LED that was redily visible throught he headlight lens that was orange when off
My P2K Geeps, my Trainline FA, a couple of my Stewart switchers - they came with an LED that was redily visible throught he headlight lens that was orange when off
Sounds liek they are still made the same then. That's part of why I went with them in the Stewart switchers, since the LED is very visible through the lens they use for the headlight. With a Yelo-Gloe LED in there, it looks like a shint reflector with a small yellow light bulb in the middle when off - if you look close enough the 'light bulb' is square but it sure beats seeing orange.
They could be different because the newest ones I bought are all at least 9 years old, most of the installed ones are even older - at least one of the Stewart switchers (those are 3mm ones, not 5mm) based on when and where I took the pictures showing how I bent the leads to match the stock LED was taken 13 years ago. Miniatronics just repackages stuff, they don;t make LEDs, switches, or much else of what they sell. So over the years, their LED supplier could easily have changed.
rrinker They could be different because the newest ones I bought are all at least 9 years old, most of the installed ones are even older - at least one of the Stewart switchers (those are 3mm ones, not 5mm) based on when and where I took the pictures showing how I bent the leads to match the stock LED was taken 13 years ago. Miniatronics just repackages stuff, they don;t make LEDs, switches, or much else of what they sell. So over the years, their LED supplier could easily have changed.
I did not realize that Miniatronics does not manufacture its own LEDs or incandescent bulbs or toggle switches. They do seem to be better quality parts than what I have purchased elsewhere.
richhotrain Mine were purchased more recently than 9 years ago, but I am not sure when exactly.
Mine were purchased more recently than 9 years ago, but I am not sure when exactly.
The 5mm YeloGlo White LEDs from Miniatronics were purchased in May 2012, so nearly 9 years ago.
The 3mm YeloGlo White LEDs from Miniatronics were purchased in March 2017, so 4 years ago.
It is the 5mm YeloGlo White LEDs from Miniatronics that are super bright.
Hmm, well, so much for that theory, they are likely identical, what I have and what you have. The only difference is probably that the 5mm ones I used are in lesser quality models with not so awesome light pipes which attentuate a good bt of the light. If I could dig one out (LED, not the loco) I could power it on my workbench and see how bright it looks with just the bare LED.
The Stewart switchers, which have 3mm versions - the light pipe lenses used for those headlights would probably qualify as optically clear, looking through one looks the same as just looking through air. The Walthers Trainline FA headlight lense, where there is a 5mm YeloGlo, well, you see light through it, you can;t read or see any detail. Same with the Atlas/Kato RS-3s - I do cut down the light pipes quite a bit, since the originals both reach to the center of the loco where a single bulb lit both headlights, but still there is a couple of inches of light pipe from the LED to the actual headlight, so all you see is the glow. I do lightly polish the cut end of the light pipe to help lkight transfer, but any interface between materials, liek the case of the LED and the light pipe plastic, is going to cause a significant loss of light output. The end of the light pipe and LED are covered in black shrink tubne, so no light escapes into the loco to shine through the shell. The extreme brightness of the 5mm YeloGlo may actually be a benefit in installs like that, but when it's in direct view or through a quality clear lens, way too bright.
I don't use light pipes on mine, so that could well be the difference.
I'm going to go down to the layout and see if I can take some good quality photos.
Stay tuned.
Here you go. Two identical Proto 2000 PA locomotives.
The one on the left has a 5mm Golden White Mars light and a 3mm Golden White Headlight.
The one on the right has a 5mm YeloGlo White Mars light and a 3mm YeloGlo White Headlight.
All of the LEDs have 1K ohm resistors attached.
richhotrain rrinker I have a bunch of loco that the headlights are the Miniatronics YeloGlow, with a 1K resistor, and they aren't excessively bright. Some are 5mm, some are 3mm. I am not very good with a camera. In fact, I am awful. But, I will try to photgraph one of my Minatronics YeloGlo LEDs with a 1K resistor. Other forum members are reporting the same brightness problem on both this thread and elsewhere on the forum. I cannot understand how your Minatronics YeloGlo LEDs with a 1K resistor installed are not too bright. Why would your LEDs be different than others? Rich
I am not very good with a camera. In fact, I am awful. But, I will try to photgraph one of my Minatronics YeloGlo LEDs with a 1K resistor. Other forum members are reporting the same brightness problem on both this thread and elsewhere on the forum. I cannot understand how your Minatronics YeloGlo LEDs with a 1K resistor installed are not too bright. Why would your LEDs be different than others?
I’m not very good at photography either but working on it. This I my Kitbash Lounge car with 10 wide angle Warm White Super Bright LEDs, 9 using 9.1KΩ resistors and one over the Bar area with a 4.7KΩ resistor.
Click on the photo to enlarge.
The newer Super Bright LEDs are very bright and I end up running them at very low current as you can see on my Mel Meters.I use a 2KΩ 20 turn trim pot in all of my passenger cars to individually set the brightness for each car through the end door.I daisy chain my passenger cars and use a rechargeable 4 volt Lithium battery with a track powered charger in the Baggage car to power the lighting.I use quick disconnect micro connector between cars, the only time I remove a car is for maintenance so the connectors between cars are not a problem for me. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
richhotrain Here you go. Two identical Proto 2000 PA locomotives. The one on the left has a 5mm Golden White Mars light and a 3mm Golden White Headlight. The one on the right has a 5mm YeloGlo White Mars light and a 3mm YeloGlo White Headlight. All of the LEDs have 1K ohm resistors attached. Rich
richhotrain rrinker My P2K Geeps, my Trainline FA, a couple of my Stewart switchers - they came with an LED that was redily visible throught he headlight lens that was orange when off I see that tiny orange speck on my Miniatronics YeloGlo White LED when off.
I see that tiny orange speck on my Miniatronics YeloGlo White LED when off.
Overmod richhotrain rrinker My P2K Geeps, my Trainline FA, a couple of my Stewart switchers - they came with an LED that was redily visible throught he headlight lens that was orange when off I see that tiny orange speck on my Miniatronics YeloGlo White LED when off. Is there some way to use half-silvered film or a small piece of glass filter to mask this from view when the light is off?
Is there some way to use half-silvered film or a small piece of glass filter to mask this from view when the light is off?
OvermodIs there some way to use half-silvered film or a small piece of glass filter to mask this from view when the light is off?
I recall posts on the forums where modelers used MV Products to hide the body of the LEDs. They removed just enough of the silvering from the center of the back of the lens to allow the light to come through.
http://www.mvproducts.com/Model-Lenses.html
This thread shows how doctorwayne used the lenses. Scroll down a bit to get to his posts:
http://cs.trains.com/mrr/f/88/p/278005/3185554.aspx#3185554
Instead of 3 resistors on each one (presumably 4.7K since that's the standard value), you can get a single 15K resistor. Or 18K or 22K.